GIOD - Database Tests (II)

  • Caltech Exemplar used as a convenient testbed for Objy multiple-client tests

  • Initial tests showed instability of lockserver

    • subsequently ran lockserver on a different machine
  • Tested clients running simulated Track reconstruction

    • CPU-intensive with modest I/O.
  • Event level (coarse-grained) parallelism

  • N = 15 - 210 reconstruction processes evenly distributed in the Exemplar system.

  • Data in an Objectivity/DB database federation

    • hosted on the Exemplar.
  • Objects read with simple read-ahead optimisation layer.

    • Performance gain of a factor 2

  • Results: Exemplar very well suited for this workload. With two (of four) node filesystems it was possible to utilise 150 processors in parallel with very high efficiency.
  • Outlook: expect to utilise all processors with near 100% efficiency when all four filesystems are engaged.
  • (Work by Koen Holtman: CHEP’98 paper)

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